MAX9729 Maxim Integrated Products, MAX9729 Datasheet - Page 21

• Manufacturer Part Number: MAX9729
• Description: Stereo Headphone Amplifier
• Manufacturer: Maxim Integrated Products

Table 6. Beep Level (Register 0x01)
Table 9. Initial Power-Up Command Register Status
Figure 8. MAX9729 Volume Control Transfer Function
BEEP level referenced to a 3V BEEP input.
The charge-pump flying capacitor connected between
C1N and C1P affects the charge pump’s load regula-
tion and output impedance. Choosing too small a flying
capacitor degrades the MAX9729’s ability to provide
sufficient current drive and leads to a loss of output
voltage. Increasing the value of the flying capacitor
improves load regulation and reduces the charge-
pump output impedance. See the Output Power vs.
Charge-Pump Capacitance and Load Resistance
REGISTER
B7
0
0
0
0
1
1
1
1
0x00
0x01
B6
0
0
1
1
0
0
1
1
Stereo Headphone Amplifier with BassMax,
100
B5
10
20
30
40
50
60
70
80
90
0
1
0
1
0
1
0
1
0
B7
1
1
0
Charge-Pump Flying Capacitor (C1)
______________________________________________________________________________________
MAX9729 VOLUME CONTROL
5
B6
0
1
TRANSFER FUNCTION
10
CODE (DECIMAL)
B5
0
1
15
BEEP LEVEL (dBV)
B4
20
0
1
-10
-20
-30
-40
-50
-52
-54
-56
25
B3
1
1
30
Volume Control, and Input Mux
B2
0
0
35
B1
1
0
B0
1
1
Shutdown mode disabled (assuming V
INR1 inputs selected, ATTEN = 16dB (A
Beep input attenuation = 56dB, BassMax enabled, A
Table 7. BassMax Control (Register 0x01)
Table 8. Maximum Gain Control
(Register 0x01)
graph in the Typical Operating Characteristics . Place
C1 physically close to C1P and C1N. Use a 1µF capac-
itor for C1 in most applications.
The hold capacitor’s value and ESR directly affect the
ripple at PV
value of the hold capacitor. Choosing a capacitor with
lower ESR reduces ripple and output impedance. Lower
capacitance values can be used in systems with low
maximum output power levels. See the Output Power vs.
Charge-Pump Capacitance and Load Resistance graph
in the Typical Operating Characteristics . C2 should be
equal to the value of C1. Place C2 physically close to
PV
C2. Use a 1µF capacitor for C2 in most applications.
The PV
ance of the power supply and reduces the impact of
the MAX9729’s charge-pump switching transients. C3
should be greater than or equal to C1. Place C3 physi-
cally close to PV
B2
0
0
0
0
1
1
1
1
SS
B3
0
1
and SV
B1
DD
0
0
1
1
0
0
1
1
bypass capacitor lowers the output imped-
B0
SS
0
1
0
1
0
1
0
1
SS
. Ripple is reduced by increasing the
. Connect PV
DD
POR SETTINGS
.
Charge-Pump Hold Capacitor (C2)
BassMax Disabled
BassMax Enabled
PV
MAXIMUM GAIN (dB)
DD
MODE
SS
SHDN
Bypass Capacitor (C3)
V_TOTAL
and SV
19.5
3.5
10
22
24
26
6
8
= V
DD
= -10dB)
SS
), INL1 and
V_MAX
together at
= 6dB
21